Anchor ring assembly

ABSTRACT

An anchor ring assembly for anchoring to a mandrel includes an annular housing which defines a through bore to permit mounting on a mandrel. A plurality of slips are circumferentially arranged within the through bore of the housing, and a plurality of activator members extend from an external surface of the housing to engage the slips. The activator members are adjustable relative to the housing to extend the slips radially inwardly to engage and grip a mandrel.

REFERENCE TO RELATED APPLICATIONS

This application is a United States National Phase application of PCTApplication No. PCT/GB2014/051210 filed on Apr. 17, 2014, which claimspriority to United Kingdom Application No. 1306968.7 filed on Apr. 17,2013.

FIELD OF THE INVENTION

The present invention relates to an anchor ring assembly for anchoringto a mandrel, for example to provide end support to seal, such as apacker for providing a seal in a wellbore annulus.

BACKGROUND TO THE INVENTION

Many industries may require components to be located and secured to amandrel, such as a tubular body. For example, in the oil and gasindustry, annular seals are frequently employed which are mounted on amandrel and function to extend radially outwardly from the mandrel toengage a bore wall, thus sealing the annulus between the mandrel andbore wall. Such a seal is often referred to as a packer. Known packersor seals in the oil and gas industry may be activated in a number ofways to be extended radially outwardly, for example by being axiallycompressed, by swelling, by inflation or the like.

In many seal designs the sealing component is located on a mandrelagainst metal end rings. Such end rings are located at one or both axialends of a sealing body, and may be secured to the mandrel by welding,via set screws or the like.

The end rings may anchor a sealing component to the mandrel.Additionally, such end rings may also function to prevent unwanted axialdeformation of the sealing component, for example due to extrusion whenexposed to a pressure differential, which might otherwise compromise theintegrity of any established seal. This may be of particular importancein swellable seal designs, wherein the end rings function to prevent orminimise axial swelling, such that the swelling of the seal may berestricted primarily to the radial direction.

Of critical importance in the design of end rings is their ability toprovide a sufficient anchor to resist any displacing forces which mightbe experienced, and in some instances a poorly anchored end ring mayresult in failure of any associated seal.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is providedan anchor ring assembly for anchoring to a mandrel, including an annularhousing defining a through bore to permit mounting on a mandrel, aplurality of slips circumferentially arranged within the through bore ofthe housing, and a plurality of activator members extending from anexternal surface of the housing to engage the slips. The activatormembers are adjustable relative to the housing to extend the slipsradially inwardly to engage and grip a mandrel.

In use, the anchor ring assembly may be mounted on a mandrel and locatedin a desired position, with the activator members then adjusted relativeto the housing to extend the slips radially inwardly to engage and gripthe outer surface of the mandrel, thus anchoring or locking the anchorring assembly to the mandrel.

The anchor ring assembly may be used in various applications. Forexample, the anchor ring assembly may be for use in defining a no-goprofile on a mandrel.

The anchor ring assembly may define or function as an end ring for aseal element, such as an annular seal element, swellable seal element,axially compressible seal element, cup seal element and/or the like. Theanchor ring assembly may be configured to resist axially applied forces,such as axial pressure forces established by exposure to a pressuredifferential across a seal element. Such resistance to axial forces maypermit the anchor ring assembly to provide support to assist the sealelement to resist extrusion.

The anchor ring assembly may be configured to provide support to a sealelement. The anchor ring assembly may be configured to secure a sealelement on or relative to a mandrel.

The anchor ring assembly may be suitable for use in securing to amandrel in the form of a tubular, such as an oilfield tubular, forexample a casing tubular, liner tubular, production tubular, tool sleeveor the like.

The activator members may include activator screws threadedly engagedwith the housing to permit adjustment to extend the respective slips.

A single activator member may be provided for each slip. In otherembodiments one slip may be associated with multiple activator members.

The activator members may be configured to engage respective rear facesof the slips. An activator member may be configured to abut a respectiveslip. In such an arrangement adjustment of an activator member relativeto the housing may function to extend an associated slip. In someembodiments an activator member may be secured to a respective slip.Such an arrangement may permit the activator member to be adjustedrelative to the housing to permit both extension and retraction of theassociated slip.

An activator member may be configured to engage a respective slipgenerally centrally thereof. For example, an activator member may beconfigured to engage a respective slip at an axial and/orcircumferential central region of said slip. Engagement of an activatormember generally centrally of a respective slip may permit a degree ofself-adjustment of said slip, for example to self-align with an outersurface of a mandrel. In one embodiment engagement of an activatormember generally centrally of an associated slip may permit said slip topivot relative to the housing. Such pivoting may be possible in multipledirections. Such an arrangement may provide a self aligning function ofthe slips.

One or more slips may define an engagement profile on a rear surfacethereof and configured to be engaged by a respective activator member.For example, such an engagement profile may include a recess, dimple,blind hole, channel or the like.

One or more slips may include a gripping profile on inwardly facingsurfaces thereof for use in gripping an outer surface of a mandrel. Sucha gripping profile may assist to increase a connection force between theanchor ring assembly and a mandrel. The gripping profile may be definedby any suitable structure, such as by individual teeth or ribs, by asurface roughness, by a knurled profile, by use of inserted materialsuch as a carbine or the like.

One or more slips may include first and second sets of gripping teeth.Said sets of gripping teeth may be orientated in opposing directions.Such an arrangement may permit the first set of gripping teeth topreferentially resist forces applied in one direction, such as one axialdirection, and the second set of gripping teeth to preferentially resistforces applied in an opposite direction, such as an opposite axialdirection. The first set of gripping teeth may be located on one axialside of a slip, and the second set of gripping teeth may be located onan opposite axial side of the slip.

One or more slips may facilitate an increase in an engagement areabetween the anchor ring assembly and a mandrel, which may permit a morerobust connection to be achieved. Further, the use of slips which areextended to engage the outer surface of the mandrel may eliminate orminimise the requirement to alter the form of the mandrel to accommodatean anchor ring assembly.

One or more slips may be profiled to correspond to a profile of amandrel. For example, one or more slips may be generally curved topermit engagement with a cylindrical mandrel. One or more slips may becurved to define a circumferential segment.

At least two, and in some embodiments all slips may be arranged suchthat circumferential ends thereof may be positioned generally adjacentto each other. This arrangement may maximise the total circumferentialslip surface area which may engage a mandrel, thus permitting a morerobust connection to be achieved.

The anchor ring assembly may include a plurality of spacer ribscircumferentially distributed around the through bore of the housing,wherein adjacent slips are separated by a respective spacer rib. Eachspacer rib may extend generally axially relative to the housing.Circumferential ends of the slips may be positioned adjacent respectivespacer ribs.

One or more spacer ribs may be integrally formed with the housing.

One or more spacer ribs may be separately formed and secured to thehousing, for example via screws or the like.

Adjacent spacer ribs may define a pocket therebetween for receiving arespective slip. Each spacer rib may define tapered side faces, whereinthe circumferential faces of each slip may define corresponding taperedfaces. Such an arrangement may facilitate radial extension andretraction of the slips, with minimal interference from the spacer ribs.Furthermore, such tapered faces of the slips and spacer ribs may permiteach slip to be appropriately guided into the circumferential groove ofthe housing upon retraction of said slips.

At least two circumferentially adjacent spacer ribs may secure a slippositioned therebetween. At least two circumferentially adjacent spacerribs may define a limit of radial movement, such as inward radialmovement, of a slip positioned therebetween. In one embodiment at leasttwo circumferentially adjacent ribs may define a minimum circumferentialseparation distance which is smaller than a circumferential dimension ofa slip positioned therebetween. At least two circumferentially adjacentribs may define a minimum circumferential separation distance which issmaller than a maximum circumferential dimension of a slip positionedtherebetween. In such an arrangement, once the slip is interposedbetween adjacent ribs, said ribs will prevent said slip from being fullyradially removed from the anchor ring assembly.

At least two circumferentially adjacent ribs may collectively define aretaining profile configured to retain a slip therebetween.

The anchor ring assembly may include a retaining arrangement configuredto retain one or more slips mounted within the housing. The retainingarrangement may be configured to retain all slips within the housing.The retaining arrangement may be configured to apply a retaining forceto one or more slips to retain said slips within the housing. Extensionof one or more slips radially inwardly may be achieved against thisretaining force. The retaining arrangement may be configured to bias oneor more slips towards a retracted configuration. In such an arrangementadjustment of one or more activator members in a direction to extend theassociated one or more slips may act against the bias of the retainingarrangement. Further, in such an arrangement adjustment of one or moreactivator members in a direction to retract the associated one or moreslips may permit the bias of the retaining arrangement to cause saidslips to be retracted.

The retaining arrangement may be mounted radially inwardly of the slips.

In one embodiment one or more slips may define a groove formed in aninner surface thereof for accommodating a retaining arrangement. Aplurality, for example all, slips may define a groove, wherein when theslips are mounted within the housing, each individual groove is alignedto receive the retaining arrangement. Such a collective groove may begenerally circumferential. In some embodiments such a collective groovemay be helical.

A groove provided in one or more slips for accommodating a retainingarrangement may define a groove width which is larger than thecorresponding width of the retaining arrangement. Such an arrangementmay permit a degree of relative motion between the slip or slips and theretaining arrangement, for example to permit compliance of the slip orslips during clamping against a mandrel.

The retaining arrangement may be configured to be mounted axiallycentrally of the slips. Such an arrangement may permit the slips to beself-aligning, for example to accommodate the profile of a mandrel. Suchan arrangement may permit each slip to pivot about the retainingarrangement, which may provide a self-alignment function.

The retaining arrangement may include a single retaining element.

The retaining arrangement may include a spring member or element.

The retaining arrangement may define a split ring spring elementconfigured to provide an outwardly directed retaining force.

At least one slip may define or include first and second grippingprofiles, wherein a retaining arrangement is located between said firstand second profiles. In such an embodiment the retaining arrangement maynot interfere with the gripping function of the slips.

The annular housing may define a circumferential groove formed in aninner surface thereof, wherein said groove is configured to accommodateone or more slips. The circumferential groove may be circumferentiallycontinuous. Alternatively, the circumferential groove may becircumferentially discontinuous. For example, multiple discrete groovesor recesses may be provided within the housing. Such discrete grooves orrecesses may define a plurality of circumferentially arranged pocketseach for receiving or accommodating one or more slips.

The circumferential groove of the housing may be profiled, wherein atleast one slip defines a corresponding profile to permit appropriatefitting of the slips within the groove.

The circumferential groove of the housing may be defined betweenopposing axial faces. Opposing axial ends of at least one slip may beprofiled to correspond with the axial faces of the housing groove.

At least one axial face of the groove may extend generally perpendicularrelative to a central axis of the housing. Such an axial face may definean annular shoulder. Such an axial face may permit load transferencebetween the housing and at least one slip.

At least one axial face of the groove may be tapered. That is, at leastone axial face of the groove may be tapered or obliquely alignedrelative to a central axis of the housing. At least one axial face of atleast one slip may be tapered to correspond and engage the tapered axialface of the groove. In use, an axial load applied on the housing, forexample from an external component, such as a seal element, may betransmitted to at least one slip via the respective tapered faces, thusapplying an inward radial force on said at least one slip. Such aninward radial force may function to increase the gripping force of theslips against a mandrel. Accordingly, increasing axial load applied onthe housing, for example from an external component, may result in thegripping force of the slips being increased. As such, the anchor ringassembly may automatically respond to changes in applied axial forces.

Opposing axial faces of the groove, and opposing axial faces of at leastone slip may be tapered. Such an arrangement may permit an increase ingripping force to be achieved in the event of an axial load applied inopposite axial directions.

At least one axial end face of the housing may be configured to beengaged by an external component, such as a seal component or element.At least one axial end face of the housing may define a load surface,such as a load shoulder or the like. Such a load surface may beconfigured for transmission of force from an external component orenvironment into the anchor ring assembly.

At least one axial end face of the housing may be tapered relative to acentral axis of the housing. Such a tapered surface may facilitate orassist with insertion of the anchor ring assembly, for example whenmounted on a mandrel, into a bore, such as a well bore.

At least one axial end face of the housing may be generallyperpendicular to central axis of housing.

At least one axial end face of the housing may be configured to besealingly engaged with an external component, such as a sealing element.

At least one axial end face of the housing may be configured to bebonded to an external component, such as a seal component or element.

At least one axial end face of the housing may be configured to define aprofile configured to permit engagement with a corresponding profile onan external component, such as a sealing element.

At least one axial end face of the housing may include an axialextension configured to engage an external component, such as a sealingelement, for example a cup seal element. The axial extension mayincrease a surface area of contact between an external component and thehousing. The axial extension may be configured to at least partiallydefine a sealed surface between the housing and an external component.The axial extension may be configured to at least partially define abonded surface between the housing and an external component.

The anchor ring assembly may include a sealing arrangement configured toprovide a seal with a mandrel. The sealing arrangement may be configuredto provide a seal between the housing and a mandrel. The sealarrangement may include a mechanical seal, such as an o-ring seal or thelike. An inner surface of the housing may define a circumferentialgroove configured to accommodate a seal, such as an o- ring seal. Aninner surface of the housing may define multiple circumferential groovesconfigured to accommodate respective seals.

The sealing arrangement may be configured to provide a seal between theslips and a mandrel. The slips may define one or more grooves configuredto collectively accommodate a seal, such as an o-ring seal.

A retaining arrangement configured to retain the slips within thecircumferential groove of the housing may also define a sealingarrangement configured to provide a seal against a mandrel.

The anchor ring assembly may include a sealing element extending fromone axial end of the housing. The sealing element may be configured foruse in providing a seal in an annulus defined between a mandrel and anouter bore wall, such as an open drilled bore wall, the wall of acasing, pipeline or the like. The anchor ring assembly, and inparticular the annular housing may provide axial support to such asealing element, for example to help resist extrusion of the sealingelement when exposed to a pressure differential.

The sealing element may include an annular sealing element.

The sealing element may include a swellable material configured to swellupon exposure to an activator, such as oil and/or water. In such anarrangement the anchor ring assembly, and in particular the housing whenanchored to a mandrel via the slips, may function to restrict swellingof the swellable material in an axial direction. In this way, swellingmay be achieved primarily in a radial direction to facilitate sealingbetween the mandrel and an outer bore wall.

The sealing element may include an axially compressible sealing element.In such an arrangement the anchor ring assembly, and in particular thehousing when anchored to a mandrel via the slips, may define a reactionpoint against which such a compressible sealing element may becompressed.

The sealing element may include a cup seal sealing element. One axialend of the cup sealing element may be engaged with the housing, forexample sealingly engaged, and an opposite axial end of the cup sealingelement may be free from support, so as to permit the seal element tofunction as a cup seal.

The sealing element may be bonded directly to a mandrel.

The sealing element may include a support sleeve, an outer sealingmaterial mounted on an outer surface of the support sleeve, and an innersealing material mounted on an inner surface of the support sleeve.

In such an arrangement the outer sealing material may be configured toestablish a seal with a wall of a bore, and the inner sealing materialmay be configured to establish a seal against a mandrel.

The support sleeve may extend along the entire axial length of thesealing element. In some embodiments the support sleeve may extend alonga partial axial length of the sealing element.

The support sleeve may be fixed to the anchor ring assembly, for exampleto the housing of the anchor ring assembly.

According to a second aspect of the present invention, there is provideda method for anchoring to a mandrel, including mounting an anchor ringassembly on a mandrel, the anchor ring assembly including an annularhousing and a plurality of slips circumferentially arranged within athrough bore of the housing, and adjusting a plurality of activatormembers which extend from an outer surface of the housing to engage therespective slips to extend the slips radially inwardly to engage andgrip the mandrel.

The anchor ring assembly according to the first aspect may be utilizedin the method according to the second aspect.

According to a third aspect of the present invention, there is provideda sealing assembly for use in providing a seal in an annulus between amandrel and a bore wall, including:

an annular housing defining a through bore to permit mounting on amandrel;

a plurality of slips circumferentially arranged within the through boreof the housing;

a plurality of activator members extending from an external surface ofthe housing to engage the slips, wherein the activator members areadjustable relative to the housing to extend the slips radially inwardlyto engage and grip a mandrel; and

a sealing element extending from one axial end of the housing.

The sealing assembly may include two annular housings located atopposite ends of the sealing element, wherein each annular housingaccommodates slips for anchoring to a mandrel. In such an arrangementthe sealing element may be supported at opposing ends.

The sealing assembly may include a single housing, such that the sealingelement is supported at a single end.

The sealing element may include any suitable type of sealing element,such as a swellable sealing element, compressible sealing element, a cupsealing element or the like.

The housing may include an axial extension extending from one axial endface thereof to permit engagement with the sealing element.

The sealing assembly may include an anchor ring assembly according tothe first aspect.

According to a fourth aspect of the present invention, there is provideda sealing assembly including: a mandrel; an annular sealing elementbonded to the outer surface of the mandrel, wherein the sealing elementincludes a swellable material configured to swell upon exposure to anactivator.

The activator may include water, oil, gas or the like.

According to a fifth aspect of the present invention, there is provideda sealing assembly including a support member, an outer swellablesealing element mounted on an outer surface of the support member, andan inner swellable sealing element mounted on an inner surface of thesupport member. The outer swellable sealing element is configured toswell to define a seal between the support member and a bore wall, andthe inner swellable sealing element is configured to swell to define aseal between the support member and a mandrel.

The sealing assembly may be configured to be mounted on a mandrel, forexample to be slipped on to one end of a mandrel.

The support member may include a metallic support member. The supportmember may be generally cylindrical. The support member may include oneor more perforations through its wall structure. The inner and outersealing elements may engage each other via these perforations. In oneembodiment the inner and outer sealing elements may be integrated, forexample continuous, via these perforations.

The sealing assembly may include one or more end rings. The supportmember may be secured or at least engage at least one end ring.

The outer sealing element may engage an axial end face or surface of anend ring.

The inner sealing element may engage an axial end face or surface of anend ring.

The inner sealing element may engage an inner circumferential face of anend ring. Such an arrangement may permit the inner sealing element toalso establish a seal between an end ring and a mandrel.

An end ring may be configured to be secured relative to the supportmember via one or more screws, such as set screws, grub screws or thelike.

An end ring may include an anchor ring assembly according to the firstaspect.

According to a sixth aspect of the present invention, there is provideda sealing assembly for use in providing a seal in an annulus between amandrel and a bore wall, including an annular housing defining a throughbore to permit mounting on a mandrel, the annular housing including asealing arrangement for providing a seal between the annular housing anda mandrel, a plurality of slips circumferentially arranged within thehousing, the slips configured to be extended radially inwardly to engageand grip a mandrel, and a cup sealing element extending from one axialend of the housing.

One axial end of the housing may include an axial extension configuredto engage the cup sealing element.

The cup sealing element may be bonded to one axial end of the housing.

The sealing arrangement provided between the housing and a mandrel mayinclude one or more mechanical seals, such as o-ring seals.

The sealing assembly may include an anchor ring assembly according tothe first aspect.

Features defined in relation to one aspect may be provided incombination with any other aspect. It should be understood that thefeatures defined above in accordance with any aspect of the presentinvention or below in relation to any specific embodiment of theinvention may be utilized, either alone or in combination with any otherdefined feature, in any other aspect or embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described,by way of example only, with reference to the accompanying drawings, inwhich:

FIG. 1 is a perspective view of an anchor ring assembly according to anembodiment of the present invention;

FIG. 2 is a side view of the anchor ring assembly of FIG. 1, shownmounted on a mandrel, wherein the mandrel is illustrated in brokenoutline;

FIG. 3 is a cross sectional view of the anchor ring assembly takenthrough line 3-3 of FIG. 2, with the mandrel removed for clarity;

FIG. 4 is a cross sectional view of the anchor ring assembly takenthrough line 4-4 of FIG. 2, with the mandrel removed for clarity;

FIG. 5 is a perspective view of a single slip which forms part of theanchor ring assembly;

FIG. 6 is a cross-section view of the anchor ring assembly taken throughline 6-6 of FIG. 2, with the mandrel removed for clarity;

FIG. 7 illustrates a sealing assembly according to an embodiment of thepresent invention, which incorporates a pair of anchor ring assemblies;

FIG. 8 illustrates a sealing assembly according to another embodiment ofthe present invention, which incorporates a pair of anchor ringassemblies;

FIG. 9 is a cross sectional view of a portion of an anchor ring assemblyaccording to an alternative embodiment of the present invention;

FIG. 10 is a perspective view of an anchor ring assembly according to analternative embodiment of the present invention;

FIG. 11 is a side view of the anchor ring assembly of FIG. 10, shownmounted on a mandrel, wherein the mandrel is illustrated in brokenoutline;

FIG. 12 is a cross sectional view of the anchor ring assembly takenthrough line 12-12 of FIG. 11, with the mandrel removed for clarity;

FIG. 13 is an enlarged view of a portion of the anchor ring assembly asshown in the section of FIG. 12, with a slip removed;

FIG. 14 illustrates a sealing assembly according to an embodiment of thepresent invention, with an end ring removed for clarity; and

FIG. 15 illustrates a sealing assembly according to an alternativeembodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

A perspective view of an anchor ring assembly, generally identified byreference numeral 10, is shown in FIG. 1, and a side view of the sameassembly 10 is illustrated in FIG. 2. As will be described in detailbelow, the anchor ring assembly 10 is for use in anchoring to a mandrel12, which is illustrated in FIG. 2 in broken outline. The mandrel 12 mayinclude a tubular member, such as an oilfield tubular. The anchor ringassembly 10 may have utility in multiple applications. In some of theexamples below the assembly 10 is utilized to function as an end ring ina sealing assembly, such as a packer assembly.

The anchor ring assembly 10 includes an annular housing 14 which definesa throughbore 15 to permit the housing 14 to be mounted on the mandrel12. The assembly 10 further includes a plurality of slips 16 (five inthe embodiment shown) which are circumferentially arranged within acircumferential groove 18 formed in an inner surface of the housing 14,wherein the slips 16 are each located between circumferentially arrangedspacer ribs 20 which are secured to the housing via screws 22, as alsoillustrated in FIG. 3 which is a cross-sectional view through line 3-3of FIG. 2. Each rib 20 includes tapered side faces 24, and thecircumferential end faces 26 of each slip 16 correspond such that theslips 16 may be permitted to be displaced radially inwardly withoutinterference from the ribs 20. Furthermore, the corresponding faces 24,26 of the ribs 20 and slips 16 may function to align the slips 16 withinthe circumferential groove 18 of the housing 14 when moved towards aretracted position.

A plurality of activator members in the form of screws 28 extend fromthe outer surface of the housing 14 and engage the rear faces of therespective slips 16, as shown in FIG. 4 which is a cross sectional viewthrough line 4-4 of FIG. 2. Adjustment of the activator screws 28relative to the housing 14 permits the slips 16 to be extended radiallyinwardly to grip the outer surface of the mandrel 12 and thus anchor theassembly 10 thereto.

A single activator screw 28 is provided for each slip 16, and each screw28 engages the rear face of a slip 16 generally centrally thereof. Thisarrangement permits the slips 16 to pivot about the contact point withthe screws 28, which assists with self-alignment of the slips 16 withthe mandrel 12.

In the present embodiment, one axial end face 30 of the housing 14 isgenerally perpendicular to a central axis of the housing 14. As bestillustrated in FIG. 2, such a perpendicular end face 30 defines anannular shoulder relative to the mandrel 12. This annular shoulder orface 30 may be used to support an adjacent external component, such as asealing element for defining a seal between the mandrel 12 and a borewall.

An opposite axial end face 32 of the housing 14 defines a taperedsurface. This may facilitate insertion of the mandrel 12 and mountedanchor ring assembly 10 into a bore, for example to minimise snagging ofthe assembly 10 with any restrictions in such a bore.

An individual slip 16 is illustrated in FIG. 5, reference to which isadditionally made. Each slip 16 is generally arcuate or curved in formand includes first and second sets of gripping profiles in the form ofsets of teeth 34, 36 which function to increase the anchoring forceagainst the mandrel 12. In the embodiment shown, the first and secondsets of gripping teeth 34, 36 are orientated in opposing directions,which permits the first set of gripping teeth 34 to preferentiallyresist forces applied in one axial direction, and the second set ofgripping teeth 36 to preferentially resist forces applied in an oppositeaxial direction.

Each slip 16 includes a central groove 38 which are aligned when theslips 16 are mounted within the housing 14. The grooves 38 areconfigured to receive a split ring spring member 40, as illustrated inFIGS. 1 and 4, which functions to retain each slip 16 within thecircumferential groove 18 of the housing 14. Further, the spring member40 applies a biasing force against the slips 16 to bias said slipstowards a retracted position, for example when the activator screws 28are adjusted relative to the housing 14 to permit retraction of theslips 16. In some embodiments the grooves 38 each are wider than thespring member 40 in the axial direction. Such an arrangement may permita degree of relative movement therebetween.

Reference is now additionally made to FIG. 6 which is a cross sectionalview of the assembly 10 taken through line 6-6 of FIG. 2. Asillustrated, the circumferential groove 18 formed in the housingincludes opposing tapered side faces 42. Further, each slip 16 includescorresponding tapered side faces 44. In use, an axial load applied onthe housing 14, for example from an external component, such as a sealelement, may be transmitted to the slips 16 via the respective taperedfaces 42, 44, thus applying an inward radial force on the slips 16. Suchan inward radial force may function to increase the gripping force ofthe slips 16 against the mandrel 12. Accordingly, increasing axial loadapplied on the housing 14, for example from an external component, mayresult in the gripping force of the slips 16 being increased. As such,the anchor ring assembly 10 may automatically respond to changes inapplied axial forces.

As noted above, the anchor ring assembly 10 may be used in multipleapplications, including as an end ring within a sealing assembly, suchas illustrated in FIG. 7. In this exemplary embodiment a sealingassembly, generally identified by reference numeral 50, includes anannular sealing element 52 which is bonded directly to the mandrel 12,and a pair of anchor ring assemblies 10, as described above, are locatedand anchored to the mandrel 12 at opposing ends of the sealing element52. The sealing element 52 may be composed of or include a swellablematerial, such as a swellable rubber, which swells when contacted by asuitable activator, such as oil and/or water.

The anchor ring assemblies 10 may function to provide axial support tothe sealing element 52, for example to assist the sealing element 52 toresist extrusion, to restrict any axial swelling and the like. Further,the anchor ring assemblies 10 may protect the sealing element 52 whilethe mandrel 12 is run into a bore.

In the present embodiment the sealing element 52 may first be bonded tothe mandrel, and the anchor ring assemblies 10 then located in place.Alternatively, the anchor ring assemblies 10 may be located on themandrel and secured in place, with the sealing element 52 then locatedand bonded to the mandrel 12.

An alternative embodiment of a sealing assembly, in this case generallyidentified by reference numeral 60, is illustrated in FIG. 8. Thesealing assembly 60 includes a sealing element 62 which is mounted aboutthe mandrel 12. However, in this case the sealing element 62 is notbonded to the mandrel 12, but instead is simply slipped over the mandrel62 and located in the desired position. A pair of anchor ring assemblies10, as described above, are mounted on the mandrel 12 at opposing endsof the sealing element.

As in the embodiment shown in FIG. 7, the sealing element 62 in FIG. 8may include a swellable material. In particular, the sealing element 62is composed of a support sleeve 64, which may be of a metalconstruction, an outer swellable layer 66 mounted on an outer surface ofthe support sleeve 64, and an inner swellable layer 68 mounted on aninner surface of the support sleeve 64. In use, the outer layer 66 mayswell to provide a seal between the support sleeve 64 and a bore wall,and the inner layer 68 may swell to provide a seal between the supportsleeve 64 and the mandrel 12. In some embodiments the sleeve 64 may beperforated such that the outer and inner swellable layers 66, 68 may beintegrated with each other through the perforations.

Reference is now made to FIG. 9 which is a cross sectional view of aportion of an anchor ring assembly, generally identified by referencenumeral 110, in accordance with an alternative embodiment of the presentinvention. Anchor ring assembly 110 is similar to that assembly 10 firstshown in FIG. 1 and as such like features share like reference numerals,incremented by 100. Accordingly, the assembly 110 includes a housing 114and a plurality of slips 116 arranged within a circumferential groove118 formed in the inner surface of the housing 114. As in the embodimentfirst shown in FIG. 1, the slips 116 in the present embodiment may beextended by use of activator screws (not shown) to grip a mandrel (alsonot shown).

In the present embodiment the housing 114 defines a pair ofcircumferential grooves 70, 72 on either side of the slips 116 which areconfigured to receive respective o-rings 74, 76. These o-rings 74, 76permit a seal to be achieved between the housing 114 and a mandrel.

One end of the housing 114 includes an axial extension 78 which in thepresent embodiment is for use in engaging an end of a sealing element80, which is shown in broken outline. The sealing element 80 is bondedto the axial extension 78, thus achieving a seal therebetween.

In the present embodiment the sealing element 80 defines a cup sealingelement, having a proximal end 82 secured to the axial extension 78, asdescribed above, and having a distal end (not illustrated) being freefrom support, such that a pressure differential across the sealingelement 80 may act to extend the distal end against a bore wall, toestablish and/or increase a seal therebetween. In this respect, theo-rings 74, 76 function to prevent leakage of fluid/pressure across theanchor ring assembly 110.

A perspective view of anchor ring assembly 210 in accordance with analternative embodiment of the present invention is shown in FIG. 1, anda side view of the same assembly 210 is illustrated in FIG. 2, shownmounted on a mandrel 212 (shown in broken outline). Anchor ring assembly210 is similar to assembly 10 first shown in FIG. 1, and as such likecomponents share like reference numerals, incremented by 200.

Accordingly, the anchor ring assembly 210 includes an annular housing214 which defines a throughbore 215 to permit the housing 214 to bemounted on the mandrel 212. The assembly 210 further includes aplurality of slips 216 (ten in this present embodiment) which arecircumferentially arranged within a circumferential groove 218 formed inan inner surface of the housing 214. The slips 216 are located betweencircumferentially arranged spacer ribs 220 which are secured to thehousing via screws 222. As will be described in more detail below, theribs 220 function to hold or retain the slips 216 within the housing214, while still permitting the slips to be moved radially. As such,additional retaining features, such as split rings, are not necessarilyrequired in the present embodiment.

A plurality of activator members in the form of screws 228 extend fromthe outer surface of the housing 214 and engage the rear faces of therespective slips 216, as shown in FIG. 12 which is a cross sectionalview through line 12-12 of FIG. 10. Adjustment of the activator screws228 relative to the housing 214 permits the slips 216 to be extendedradially inwardly to grip the outer surface of the mandrel 212 and thusanchor the assembly 210 thereto.

In the present embodiment one axial end face 230 of the housing 214 isgenerally perpendicular to a central axis of the housing 214, and anopposite axial end face 232 of the housing 214 defines a taperedsurface.

In a similar manner to the slips 16 of assembly 10, the slips 216 in thepresent embodiment define an arcuate inner surfaces which include agripping profile in the form of teeth 35. However, in the presentembodiment the teeth are arranged in a common direction.

As noted above, the ribs 220 function to retain the slips 216 within thehousing. In this respect, reference is now made to FIG. 13, which is anenlarged view of a portion of the anchor ring assembly 210 as shown inthe section of FIG. 12, with a slip 216 a removed from a pocket 90defined between two circumferentially adjacent ribs 220 a, 220 b. Theribs 220 a, 22 b are formed and arranged within the housing 214 todefine a radially inner circumferential separation distance 92 which issmaller than the radially outer circumferential length 94 of the slip216 a. Accordingly, once the slip 216 a is mounted within the pocket 90,and the ribs 220 a, 220 b are securely fastened to the housing 214, theslip 216 a will not be permitted to be removed, yet will be permitted tomove radially within the housing to selectively grip and release amandrel 212.

Reference is now made to FIG. 14 of the drawings in which there is showna sealing assembly, generally identified by reference numeral 300, inaccordance with an embodiment of the present invention. The assembly 300is adapted to be slipped over a mandrel (not shown), and located in thedesired position, thus providing a degree of freedom on where and whento apply the sealing assembly 300.

The assembly 300 includes a sealing component 302 which extends betweenopposing end rings 304, wherein one end ring is shown removed from theassembly 300 to reveal features of the sealing component 302. The endrings 304 may function to secure the entire assembly 300 to a mandrel.

The sealing component 302 includes a support sleeve 308 which may be ofa metal construction and which extends between the end rings 304. Anouter swellable seal layer 310 is mounted on an outer surface of thesupport sleeve 308, wherein the outer layer 310 is axially shorter thanthe support sleeve 308. An inner swellable seal layer 312 is mounted onan inner surface of the support sleeve 308, wherein the inner layer 312is axially longer than the support sleeve 308. In use, the outer layer310 may swell to provide a seal between the support sleeve 308 and abore wall, and the inner layer 312 may swell to provide a seal betweenthe support sleeve 308 and a mandrel, thus achieving a complete annularseal between the mandrel and bore wall.

The end rings 304 may be mounted relative to the sealing component 302such that an end face 314 of the rings 304 abuts or engages the outerseal layer 310, whereas an inner surface of the ends rings 304 engagesor abuts the support sleeve 308 and optionally the inner seal layer 312.In this respect, swelling of the inner layer 312 may function toestablish a seal against the end rings 304, for example between the endrings 304 and a mandrel.

In an alternative embodiment, which is not illustrated, the supportsleeve 308 and outer and inner seal layers 310, 312 may be of equalaxial lengths. In a further alternative embodiment, the support sleeve308 may be axially shorter then the inner and outer seal layers 310,312. Further, the support sleeve 308 may be perforated, and the innerand outer seal layers 310, 312 may engage, for example be integrallyformed, through the perforations.

Reference is now made to FIG. 15 which illustrates a sealing assembly,generally identified by reference numeral 320, in accordance with analternative embodiment of the present invention, wherein the sealingassembly 320 is shown mounted on a mandrel 322, such as an oilfieldtubular. In certain embodiments the mandrel 322 may form part of thesealing assembly 320. The mandrel 322 may be provided in the form of apup joint. The mandrel 322 may include threaded connectors 328, 329 atopposing ends thereof. Connector 328 may be a pin type threadedconnector, whereas connector 329 may be a box type threaded connector.

The sealing assembly 320 includes a swellable seal element 324 which isdirectly bonded to the outer surface of the mandrel 322. Such bondingmay be achieved by use of an adhesive. Such bonding may be achieved bymounting the swellable material of the seal element 324 on the mandrel,and then vulcanising the material to cause the element 324 to becomebonded to the mandrel 322.

The sealing assembly 320 further includes a pair of end rings 326mounted at opposite ends of the sealing element 324, and may be used toprotect and axially support the seal element 324.

It should be understood that the embodiments described herein are merelyexemplary and that various modifications may be made thereto withoutdeparting from the scope of the invention. For example, the anchor ringassemblies may be for use in other applications beyond providing supportto a sealing element or component, such as in establishing a no-go on amandrel. Further, in some embodiments one, some or all of the ribs (suchas ribs 22 or ribs 220) may be integrally formed with the housing.

The foregoing description is only exemplary of the principles of theinvention. Many modifications and variations of the present inventionare possible in light of the above teachings. The preferred embodimentsof this invention have been disclosed, however, so that one of ordinaryskill in the art would recognize that certain modifications would comewithin the scope of this invention. It is, therefore, to be understoodthat within the scope of the appended claims, the invention may bepracticed otherwise than as specifically described. For that reason thefollowing claims should be studied to determine the true scope andcontent of this invention.

1. An anchor ring assembly for anchoring to a mandrel, comprising: anannular housing defining a through bore to permit mounting on a mandrel;a plurality of slips circumferentially arranged within the through boreof the housing; and a plurality of activator members extending from anexternal surface of the housing to engage the slips, wherein theactivator members are adjustable relative to the housing to extend theslips radially inwardly to engage and grip a mandrel.
 2. The anchor ringassembly according to claim 1, wherein the activator members compriseactivator screws threadedly engaged with the housing to permitadjustment to extend the respective slips.
 3. The anchor ring assemblyaccording to claim 1, wherein a single activator member is provided foreach slip.
 4. The anchor ring assembly according to claim 1, wherein theactivator member engage respective rear faces of the slips.
 5. Theanchor ring assembly according to claim 1, wherein an activator memberis configured to engage a respective slip generally centrally thereof.6. The anchor ring assembly according to claim 1, wherein at least oneof: at least one slip defines an engagement profile on a rear surfacethereof to be engaged by a respective activator member; at least oneslip comprises a gripping profile on inwardly facing surface thereof foruse in gripping an outer surface of a mandrel; at least one slipcomprises gripping teeth; at least one slip comprises first and secondsets of gripping teeth; at least one slip comprises first and secondsets of gripping teeth and the first and second sets of gripping teethare orientated in opposing directions; at least one slip defines acurved profile. 7-11. (canceled)
 12. The anchor ring assembly accordingto claim 1, comprising a plurality of spacer ribs circumferentiallydistributed around the through bore of the housing, wherein adjacentslips are separated by a respective spacer rib.
 13. The anchor ringassembly according to claim 12, wherein at least one of: each spacer ribextends generally axially relative to the housing; adjacent spacer ribsdefine a pocket therebetween for receiving a respective slip; eachspacer rib defines tapered side faces, wherein the circumferential facesof each slip define corresponding tapered faces; at least twocircumferentially adjacent spacer ribs retain a slip positionedtherebetween within the assembly; at least two circumferentiallyadjacent spacer ribs define a limit of radial movement of a slippositioned therebetween; at least two circumferentially adjacent ribsdefine a minimum circumferential separation distance which is smallerthan a circumferential dimension of a slip positioned therebetween: atleast two circumferentially adjacent ribs define a minimumcircumferential separation distance which is smaller than a maximumcircumferential dimension of a slip positioned therebetween; at leasttwo circumferentially adjacent ribs collectively define a retainingprofile configured to retain a slip therebetween. 14-20. (canceled) 21.The anchor ring assembly according to claim 1, comprising a retainingarrangement configured to retain one or more slips mounted within thehousing.
 22. The anchor ring assembly according to claim 21, wherein atleast one of: the retaining arrangement is configured to apply aretaining force to one or more slips to retain said slips within thehousing; the retaining arrangement biases one or more slips towards aretracted configuration; the retaining arrangement is mounted radiallyinwardly of the slips; one or more slips define a groove formed in aninner surface thereof for accommodating a retaining arrangement; eachslip defines a groove, wherein when the slips are mounted within thehousing each individual groove is aligned to receive the retainingarrangement; the retaining arrangement is mounted axially centrally ofthe slips; the retaining arrangement comprises a spring member orelement, such as a split spring element; at least one slip comprisesfirst and second axially separated gripping profiles, wherein aretaining arrangement is located between said first and second profiles.23-29. (canceled)
 30. The anchor ring assembly according to claim 1, theannular housing defines a circumferential groove formed in an innersurface thereof, wherein said groove is configured to accommodate one ormore slips.
 31. The anchor ring assembly according to claim 30, whereinat least one of: the circumferential groove is profiled, wherein atleast one slip defines a corresponding profile to permit appropriatefitting of the slips within the groove; at least one axial face of thegroove is tapered, and at least one axial face of at east one slip istapered to correspond and engage the tapered axial face of the groove;opposing axial faces of the groove, and opposing axial faces of at leastone slip are tapered. 32-33. (canceled)
 34. The anchor ring assemblyaccording to claim 1, wherein at least one of: at least one axial endface of the housing defines a load surface; and at least one axial endface of the housing is tapered relative to a central axis of thehousing.
 35. (canceled)
 36. The anchor ring assembly according to claim1, wherein at least one axial end face of the housing comprises an axialextension configured to engage an external component, such as a sealingelement.
 37. The anchor ring assembly according to claim 1, comprising asealing arrangement configured to provide a seal with a mandrel.
 38. Theanchor ring assembly according to claim 1, comprising a sealing elementextending from one axial end of the housing.
 39. A method for anchoringto a mandrel, comprising: mounting an anchor ring assembly on a mandrel,wherein the anchor ring assembly comprises an annular housing and aplurality of slips circumferentially arranged within a through bore ofthe housing; and adjusting a plurality of activator members which extendfrom an outer surface of the housing to engage the respective slips toextend the slips radially inwardly to engage and grip the mandrel.
 40. Asealing assembly for use in providing a seal in an annulus between amandrel and a bore wall, comprising: an annular housing defining athrough bore to permit mounting on a mandrel; a plurality of slipscircumferentially arranged within the through bore of the housing; aplurality of activator members extending from an external surface of thehousing to engage the slips, wherein the activator members areadjustable relative to the housing to extend the slips radially inwardlyto engage and grip a mandrel; and a sealing element extending from oneaxial end of the housing.
 41. The sealing assembly according to claim40, comprising two annular housings located at opposite ends of thesealing element, wherein each annular housing accommodates slips foranchoring to a mandrel.
 42. A sealing assembly comprising: a mandrel;and an annular sealing element bonded to the outer surface of themandrel, wherein the sealing element comprises a swellable materialconfigured to swell upon exposure to an activator.
 43. A sealingassembly comprising: a support member; an outer swellable sealingelement mounted on an outer surface of the support member; and an innerswellable sealing element mounted on an inner surface of the supportmember, wherein the outer swellable sealing element is configured toswell to define a seal between the support member and a bore wall, andthe inner swellable sealing element is configured to swell to define aseal between the support member and a mandrel.
 44. The sealing assemblyaccording to claim 43, configured to be mounted on a mandrel.
 45. Thesealing assembly according to claim 43, wherein at least one of: thesupport member comprise a metallic support member: the support member isgenerally cylindrical; the support member comprises one or moreperforations through its wall structure; the support member comprisesone or more perforations through its wall structure, the inner and outersealing elements engage, for example by being integrally formed, via theperforations. 46-48. (canceled)
 49. The sealing assembly according toclaim 43, comprising one or more end rings.
 50. The sealing assemblyaccording to claim 49, wherein at least one of: the support memberengages at least one end ring; the outer sealing element engages anaxial end face or surface of an end ring; the inner sealing elementengages an axial end face or surface of an end ring; the inner sealingelement engages an inner circumferential face of an end ring; and an endring is secured relative to the support member via one or more screws.51-54. (canceled)
 55. A sealing assembly for use in providing a seal inan annulus between a mandrel and a bore wall, comprising: an annularhousing defining a through bore to permit mounting on a mandrel, whereinthe annular housing includes a sealing arrangement for providing a sealbetween the annular housing and a mandrel; a plurality of slipscircumferentially arranged within the housing, wherein the slips areconfigured to be extended radially inwardly to engage and grip amandrel; and a cup sealing element extending from one axial end of thehousing.
 56. The sealing assembly according to claim 55, wherein oneaxial end of the housing includes an axial extension configured toengage the cup sealing element.
 57. The sealing assembly according toclaim 55, wherein the cup sealing element is bonded to one axial end ofthe housing.
 58. The anchor ring assembly according to claim 1, whereinthe activator members are adjustable radially inwards relative to thehousing to extend the slips radially inwardly to engage and grip amandrel.